Use HTML in the summary

README.md

@@ -36,11 +36,7 @@ cargo install rustlings@6.0.0-beta.3
 ```
 
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 <!-- TODO: Remove @6.0.0-beta.x -->
 
@@ -86,11 +82,7 @@ This will start the _watch mode_ which walks you through the exercises in a pred
 It will rerun the current exercise automatically every time you change the exercise's file in the `exercises/` directory.
 
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 You can add the `--manual-run` flag (`rustlings --manual-run`) to manually rerun the current exercise by entering `r` or `run` in the watch mode.